Forest and timber

Timber moves with the air around it, and the verb German uses for wood taking up water has two conjugations. quellen in the sense this list needs is strong and intransitive: das Brett quillt, es quoll, es ist gequollen — a vowel change in the present, another in the past, and sein in the perfect, because the wood is not doing anything to anything. Beside it stands a weak, transitive quellen that means to soak something so that it swells: man quellt die Erbsen über Nacht, sie hat die Bohnen gequellt. The strong verb says what happens to a thing; the weak one says what somebody does to it. In the sawmill and the joiner’s shop the strong forms are the ones you hear, since the swelling there is something the timber does by itself: a door that sticks after a wet week ist gequollen, and nobody hat it gequellt.